http://en.wikipedia.org/wiki/Federal_As ... eapons_Ban
The Centers for Disease Control and Prevention studied the "assault weapon" ban and other gun control attempts, and found "insufficient evidence to determine the effectiveness of any of the firearms laws reviewed for preventing violence," noting "that insufficient evidence to determine effectiveness should not be interpreted as evidence of ineffectiveness."[7] A 2004 critical review of research on firearms by a National Research Council panel also noted that academic studies of the assault weapon ban "did not reveal any clear impacts on gun violence" and noted "due to the fact that the relative rarity with which the banned guns were used in crime before the ban ... the maximum potential effect of the ban on gun violence outcomes would be very small...."[8]
In 2004, a research report submitted to the United States Department of Justice and the National Institute of Justice found that should the ban be renewed, its effects on gun violence would likely be small, and perhaps too small for reliable measurement, because rifles in general, including rifles referred to as "assault rifles" or "assault weapons", are rarely used in gun crimes.
Sorry, the devil made me do it. 